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Nickel Alloy BNi-2 AS-BRAZED

Heat-treated state

UNS N99620 · ASTM A5.8 BNi-2 · ISO B-Ni2 · also Nicrobraz 30

Reference condition for design: joint strength on 304/316 or Ni-alloy base metal with 0.025–0.075 mm gap.

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Values for the AS-BRAZED condition

What is BNi-2 AS-BRAZED?

BNi-2 AS-BRAZED is BNi-2 heat treated to AS-BRAZED — reference condition for design: joint strength on 304/316 or Ni-alloy base metal with 0.025–0.075 mm gap. BNi-2 AS-BRAZED has a tensile strength of 690 MPa (100 ksi), weaker than 57% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi). BNi-2 AS-BRAZED has a density of 7.9 g/cm³ (0.285 lb/in³), lighter than 92% of nickel alloy grades. It melts at 971°C (1,780 °F).

Advantages

  • Conducts heat well — 30 W/m·K (17.3 BTU/hr·ft·°F), better than 93% of nickel alloy grades

Limitations

  • Limited ductility — 2%, worse than 95% of nickel alloy grades
  • Hard to polish — 55/100, worse than 95% of nickel alloy grades
  • Difficult to machine — 10/100, worse than 93% of nickel alloy grades
  • Limited formability — 5/100, worse than 91% of nickel alloy grades
  • Needs corrosion protection — 62/100, worse than 87% of nickel alloy grades

BNi-2 AS-BRAZED properties

Typical room-temperature values for BNi-2 AS-BRAZED; 5 are specific to this condition. Other listed values are BNi-2 reference data and may not represent this condition. Bars are the position among nickel alloy grades.

Physical3

BNi-2 AS-BRAZED has a density of 7.9 g/cm³ (0.285 lb/in³), lighter than 92% of nickel alloy grades. It melts at 971°C (1,780 °F).

Density7.9 g/cm³0.29 lb/in³
Melting Point (Solidus)971°C1,780 °F
Liquidus Temperature999°C1,830 °F

Mechanical7

BNi-2 AS-BRAZED has a tensile strength of 690 MPa (100 ksi), weaker than 57% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi).

Elastic (Young's) Modulus200 GPa29 Msi
Poisson's Ratio0.3
Tensile Strength (Ultimate)690 MPa100 ksi
Elongation at Break2%
Shear Strength380 MPa55.1 ksi
Hardness, Rockwell C42 HRC
Hardness, Vickers400 HV

Thermal6

BNi-2 AS-BRAZED is rated for continuous service to 870°C (1,598 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), better than 93% of nickel alloy grades. Thermal expansion is 12.8 µm/m·K (7.11 µin/in·°F).

Thermal Conductivity30 W/m·K17.3 BTU/hr·ft·°F
Specific Heat Capacity460 J/kg·K0.11 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)12.8 µm/m·K7.1 µin/in·°F
Latent Heat of Fusion280 J/g120 BTU/lb
Max Service Temperature (continuous)870°C1,598 °F
Min Service Temperature-196°C-321 °F

Electrical1

Magnetic Responseweakly magnetic — Ni-rich matrix retains slight ferromagnetism, much reduced by Cr/Si/B

Chemical & Environmental2

Corrosion resistance is good (62/100), worse than 87% of nickel alloy grades.

Corrosion ResistanceGood62/100
Chemical Resistance SummaryGood resistance to hot gases, steam, oil and mildly oxidising media; adequate in most stainless-steel service. Attacked by strong oxidising acids (HNO3), wet halogens and hot mineral acids; the boride-rich eutectic zone is the preferential corrosion path, so favour thin, well-fitted joints.

Sustainability4

Producing a kilogram of BNi-2 AS-BRAZED takes about 170 MJ of energy and emits 13 kg of CO₂ — more than 61% of nickel alloy grades. Typical recycled content is 15%.

Embodied Energy (primary production)170 MJ/kg73,087 BTU/lb
Embodied Carbon (primary production)13 kg CO₂/kg
Embodied Water300 L/kg35.9 gal/lb
Typical Recycled Content15%

Manufacturability6

BNi-2 AS-BRAZED's machinability is not recommended (10/100, worse than 93% of nickel alloy grades); weldability poor (15/100); formability not recommended (5/100).

MachinabilityNot recommended10/100
WeldabilityPoor15/100
Formability (cold)Not recommended5/100
Brazeability / SolderabilityExcellent96/100
PolishabilityGood55/100
Anodizing Responsen/a — nickel-base braze filler is not anodised

Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.

Working with BNi-2 AS-BRAZED

Is BNi-2 easy to machine?

Solidified BNi-2 is boride-hardened and effectively unmachinable — remove excess fillets by grinding or diamond wheel, and design for minimal cleanup.

Can BNi-2 be welded?

Not a welding consumable; avoid fusion welding over a BNi-2 joint since remelted boride eutectic cracks readily.

Can BNi-2 be formed, bent or molded?

Supplied as powder, paste, tape, sintered preform or rapidly solidified amorphous foil — only the foil can be stamped or wrapped; cast bar is brittle.

What surface finishes work on BNi-2?

Braze in vacuum, dry hydrogen or argon at 1010–1177 °C with 0.025–0.075 mm gaps; passivate or electropolish the assembly afterwards, and do not plate over exposed braze fillets without masking.

BNi-2 chemical composition (wt %)

Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.

ElementSpec limit (wt %)Nominal
Cr6 – 87
Si4 – 54.5
Bmelting-point depressant; causes base-metal erosion/boride formation2.75 – 3.53.1
Fe2.5 – 3.53
C≤ 0.060.03
P≤ 0.02
S≤ 0.02
Al≤ 0.05
Ti≤ 0.05
Zr≤ 0.05
Co≤ 0.1
Se≤ 0.01
Other, totalsum of unspecified residuals≤ 0.5
Ni≈79 % nominalbalance

BNi-2 AS-BRAZED — frequently asked

What is BNi-2 AS-BRAZED used for?

BNi-2 AS-BRAZED is typically used for stainless steel honeycomb seals, heat exchanger brazing, jet engine components and general vacuum furnace brazing. In short: most widely used nickel braze; strong gap-filling and flow; melts at 971 °C.

What is the tensile strength of BNi-2 AS-BRAZED?

BNi-2 AS-BRAZED has a typical tensile strength of 690 MPa (100 ksi) — weaker than 57% of nickel alloy grades.

Is BNi-2 AS-BRAZED easy to machine?

Not especially — machinability is rated not recommended (10/100, worse than 93% of nickel alloy grades). Solidified BNi-2 is boride-hardened and effectively unmachinable — remove excess fillets by grinding or diamond wheel, and design for minimal cleanup.

Can BNi-2 AS-BRAZED be welded?

Not readily — weldability is rated poor (15/100). Not a welding consumable; avoid fusion welding over a BNi-2 joint since remelted boride eutectic cracks readily.

What surface finishes work on BNi-2 AS-BRAZED?

Braze in vacuum, dry hydrogen or argon at 1010–1177 °C with 0.025–0.075 mm gaps; passivate or electropolish the assembly afterwards, and do not plate over exposed braze fillets without masking.

Can BNi-2 AS-BRAZED be formed, bent or molded?

Supplied as powder, paste, tape, sintered preform or rapidly solidified amorphous foil — only the foil can be stamped or wrapped; cast bar is brittle.

What is the maximum service temperature of BNi-2 AS-BRAZED?

BNi-2 AS-BRAZED is rated for continuous use to about 870°C (1,598 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.

Sources

  1. AWS A5.8M/A5.8 — Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
  2. ASM Handbook Vol. 6 — Welding, Brazing, and Soldering (nickel braze filler metals) — ASM International (1993)
  3. Brazing Handbook, 5th ed. — American Welding Society (2007)
  4. Nickel braze filler metal datasheets (BNi-2 / Nicrobraz 30 class, powder, paste, tape, amorphous foil) — Wall Colmonoy / Lucas-Milhaupt / Metglas (2023)

Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.